This code converter should be very similar in the "conversion action," since both it and Telerik's use the NRefactory open source conversion engine. Both have enabled "snippet conversion," and both enabled conversion from either C# to VB or vice versa.
Where the Telerik Converter starts to be most different is in all of the UX improvements, such as:
Ajax support for code conversion
Easy, tab-based access to converted source, formatted source, and HTML
Support for "batch" conversions (via ZIP upload)
Support for "gadget" converters, such as Google Gadgets and WIndows Sidebar
Both are good free services, though, so feel free to use whichever you prefer. If there is anything we can do to improve the Telerik converter, just let me know.